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time: Introduce jiffies64_to_nsecs() 

This will be needed for the cputime_t to nsec conversion.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Link: http://lkml.kernel.org/r/1485832191-26889-2-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
zero-colors
Frederic Weisbecker 2017-01-31 04:09:17 +01:00 committed by Ingo Molnar
parent 93825f2ec7
commit 07e5f5e353
3 changed files with 18 additions and 0 deletions
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2
include/linux/jiffies.h
View File

@ -293,6 +293,8 @@ static inline u64 jiffies_to_nsecs(const unsigned long j)
return (u64)jiffies_to_usecs(j) * NSEC_PER_USEC;
}
extern u64 jiffies64_to_nsecs(u64 j);
extern unsigned long __msecs_to_jiffies(const unsigned int m);
#if HZ <= MSEC_PER_SEC && !(MSEC_PER_SEC % HZ)
/*

10
kernel/time/time.c
View File

@ -702,6 +702,16 @@ u64 nsec_to_clock_t(u64 x)
#endif
}
u64 jiffies64_to_nsecs(u64 j)
{
#if !(NSEC_PER_SEC % HZ)
return (NSEC_PER_SEC / HZ) * j;
# else
return div_u64(j * HZ_TO_NSEC_NUM, HZ_TO_NSEC_DEN);
#endif
}
EXPORT_SYMBOL(jiffies64_to_nsecs);
/**
* nsecs_to_jiffies64 - Convert nsecs in u64 to jiffies64
*

6
kernel/time/timeconst.bc
View File

@ -98,6 +98,12 @@ define timeconst(hz) {
print "#define HZ_TO_USEC_DEN\t\t", hz/cd, "\n"
print "#define USEC_TO_HZ_NUM\t\t", hz/cd, "\n"
print "#define USEC_TO_HZ_DEN\t\t", 1000000/cd, "\n"
cd=gcd(hz,1000000000)
print "#define HZ_TO_NSEC_NUM\t\t", 1000000000/cd, "\n"
print "#define HZ_TO_NSEC_DEN\t\t", hz/cd, "\n"
print "#define NSEC_TO_HZ_NUM\t\t", hz/cd, "\n"
print "#define NSEC_TO_HZ_DEN\t\t", 1000000000/cd, "\n"
print "\n"
print "#endif /* KERNEL_TIMECONST_H */\n"